[PATCH] kernel: events: callchain: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

* [PATCH] kernel: events: callchain: Replace rcu_assign_pointer() with RCU_INIT_POINTER()
@ 2014-08-22 14:15 Andreea-Cristina Bernat
  2014-09-09 14:52 ` [tip:perf/core] perf/callchain: " tip-bot for Andreea-Cristina Bernat
  0 siblings, 1 reply; 2+ messages in thread
From: Andreea-Cristina Bernat @ 2014-08-22 14:15 UTC (permalink / raw)
  To: a.p.zijlstra, paulus, mingo, acme, linux-kernel; +Cc: paulmck

The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1.   This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.

The following Coccinelle semantic patch was used:
@@
@@

- rcu_assign_pointer
+ RCU_INIT_POINTER
  (..., NULL)

Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
---
 kernel/events/callchain.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 97b67df..f2a88de 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -52,7 +52,7 @@ static void release_callchain_buffers(void)
 	struct callchain_cpus_entries *entries;
 
 	entries = callchain_cpus_entries;
-	rcu_assign_pointer(callchain_cpus_entries, NULL);
+	RCU_INIT_POINTER(callchain_cpus_entries, NULL);
 	call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
 }
 
-- 
1.9.1


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